Striker mechanisms in particular for power actuated tools



Aug. 21, 1962 J. BUMILLER 3,049,714

STRIKER MEcHANIsMs, 1N PARTICULAR FOR POWER ACTUATED TooLs Filed Jan. 28, 1960 United States Patent Gniice 3,49,7l4 Patented Aug. 21, 1952 3,049,714 STRIKER MECHANISMS lN PARTICULAR FR POWER ACTUATED TOLS Jacques Burniller, Valence, France, assigner, by mesne assignments, to Sarmi, SA., Societa @Applications de Recherches Minieres et Industrielles, Lenzerheide (Grisons), Switzerland Filed lan. 28, 196), Ser. No. 5,187 Claims priority, application France .lun-e 12, 1959 Claims. (Cl. 1-44.5)

The applicant has already devised a striker mechanism more particularly adapted for use in power actuated tools and comprising, on the o-ne hand, a permanent magnet and, on the other hand, an armature of magnetic metal, one of these elements being connected tol striker means and subjected to the action of elastic means biasing it forwardly, the other element being connected to a trigger. the arrangement being such that when the trigger is depressed, the latter drives the armature-permanent magnet unit rearwardly until the force exerted by the elastic means compressed by this rearward movement exceeds the coercive force of the magnet and suddenly throws forwardly the striker means and the element connected thereto.

Such a device is described in the U.S. patent application Serial No. 775,484 led on November 2l, 1958.

Experience has shown that it is advantageous to arrange that magnet so that it is stationary, thereby allowing the use of a bigger magnet and protecting it from dirt with improved magnetic adhesion of the armature to the magnet as a consequence.

The present invention therefore relates to a modification of the arrangement of the permanent magnet striker mechanism mentioned hereinbefore, this modification being characterized in that the permanent magnet is held stationary in the breech and the trigger acts on elastic means biasing the armature connected to the striker (with a force increasing with that exerted on the trigger when iiring or actuating the tool) away from the permanent magnet so as to throw the striker forwardly, elastic return means being provided to return the trigger to the loaded position and the armature to its position in which it is magnetically held against the permanent magnet.

In a preferred embodiment of the new arrangement, the permanent magnet striker mechanism is also characterized by the following features and combinations thereof:

The permanent magnet is removably mounted as to be stationary in a housing provided at the rear of the breech;

The armature is in the form of a cylinder parallel with the axis of the barrel;

The elastic means biasing the armature away from the permanent magnet comprises a compression coil spring which surrounds the armature and whose ends bear respectively against the forward part of the 'armature and against a control element which is slidable in a direction parallel with the axis of the barrel and is connected to the trigger;

The control element is in the form of a fork which embraces the armature and is movable along the armature between parts of the latter constituting abutments for the fork;

The armature has two opposed fiat faces whose ends forming shoulders constitute the abutments for the fork;

The elastic return means adapted to return the trigger to the loaded position and the armature to the position in which it is held magnetically against the permanent magnet comprise a coil spring which is disposed in the breech and whose ends bear respectively against the obturating element of the tool (which element has an aperture for the passage of the striker) land against a ring resting against the forward face of the fork.

Further features and advantages of the invention will be apparent from the ensuing description of an embodiment of the new permanent magnet striker mechanism to which the invention is in no way limited and which is shown in the accompanying drawing in which:

FIG. l is a longitudinal sectional view of the part of the power actuated tool comprising the permanent magnet striker' mechanism, the trigger being at rest, and

FlG. 2 is a view similar to FIG. l, showing the beginning of actuation of the trigger, the armature still being held magnetically against the permanent magnet.

The accompanying drawing shows the case 31 of the tool which carries the breech 32 and is rigid with the grip 33. Disposed in the breech 32 is the obturating element 34 provided with an aperture 35 for the passage of the striker 36 referred to hereinafter. Located forward of the element 34 is the pivotal barrel support 37 in an axial aperture of which the rear end of the barrel 3S extends. A pin 39 with its guiding head 4d is engaged in the barrel 3S and is driven out of the latter by the firing of a cartridge disposed in the cartridge carrier 4l which is in the loading chamber provided at the rear of the barrel support 37, in front of the aperture 3S.

The strik-er mechanism according to the invention comprises a permanent magnet 42 disposed, with interposi tion of a socket l43 of non-magnetic metal, in a cavity formed in a sleeve 44 which is held against the breech 32 by the inner end of the case 3l, the magnet being retained in its cavity by =a split ring 45.

Co-operable with the magnet 42 is the rear end of a cylindrical armature 46 whose forward end carries the striker 36. The rear end of the armature 46 is secured to the front end of the slidabfle socket 43y so that said armature is guided co-axially to the magnet 42. This armature 46 has two opposed flat faces 46a in sliding contact with the two branches of a fork 47 which embraces the armature and is rigid with a rod 47a teranimating in a lug 47!) which is engaged by a tooth 48a formed in the trigger 48 pivotally mounted at 49.

Disposed on the armature 46 is a coil spring 50 which acts as a striker or percussion spring, whose forward end bears against a circular clip 51 engaged in a groove pro- 5 vided in the forward part of the armature 46 and whose rear end bears against a shaped ring 52 surrounding the armature along which it is slidable so that this ring is urged against the fork 47.

A second coil spring 53, of larger diameter than the `spring 50, acts as a return spring, and bears at its'ends against the ring S2 and the obturafting element 34 respectively.

in their inoperative positions of rest, ythe various elements are disposed as shown in FIG. 1; the spring 53 biases the fork 47 rearwardly and permits the armature 46 to be magnetically held against the perinanent magnet 42. The spring Sil holds the fork 47 in its position of maximum withdrawal relative to the armature 46.

When it is desired to actuate or fire the tool, the trigger 49 is depressed (FIG. 2), the unit 47-47a-47b is pulled forward and the spring S3 is compressed. The stri-ker spring Sil is al-so initially compressed, since the armature -46 remains magnetically held against the permanent magnet 42.

When the force exerted by the striker spring Si) is sufficlent to overcome lthe coercive force of the magnet 42 (or when the fork 47 abuts the forward ends of the flat faces 46a constituting shoulders), the armature 46 is pulled away from the magnet and, under ythe effect of the stressed -spring 50, is thrown forward in the cou-rse of which movement the striker 36, in passing through the aperture 35, strikes the cap of the cartridge.

When the trigger 49 is released, all the elements are caused, by the action of the springs 50 and 53, to resume the positions shown in FIG. 1 and the armature is once more magnetically held against the magnet.

It must be understood that the embodiment of the new permanent magnet striker mechanism de-scribed hereinbefore and shown 'm the accompanying drawing has been given merely by way of example, and any modification can `be made therein.

What I claim is:

l. Striker mechanism for power actuated tool, comprising a breech having a rear axial cavity and manual control means for said 4mechanism Which comp-rises: a permanent magnet mounted in the cavity of the i treech; a rod of magnetic material which is parallel With the longitudinal axis yof the tool and whose rear end is attracted by said magnet; .a striker carried by the forward end of said rod; connecting means operatively connected to said control means and slidable along said rod; and elastic loading means Ibearing with one end -against the forward end of -said rod and with the other end against said connecting means and thereby being compressed when said control means are actuated.

2. Striker mechanism as claimed in claim 1, further comprising a guide socket fixed to the magnet-engaging end of said rod and slidably surrounding said magnet thereby maintaining said rod vand said magnet in axial position relative to each other.

3. Striker mechanism as claimed in claim 1, further comprising elastic return means for returning said rod to said magnet lwhen said control means are no longer actuated.

4. Striker mechanism as claimed in claim 3, wherein said elastic return means comprise a coil spring surrounding said rod and bearing against said connecting means.

5. Striker mechanism as claimed in claim 1, wherein the connecting means comprise a member slidable in the breech in a direction parallel with said rod and having at one end a lug which is movable by said control means and at -its other end a fork the branches of which embrace said roof.

6. Striker mechanism for use iin a power actuated tool comprising a breech, `a guiding member mounted at the rear `of the breech `and having a longitudinal cavity, a barrel carried by said breech, an obturating element intermediate said longitudinal cavity `and said barrel, and a trigger for controlling said `striker mechanism, the latter comprising: a Irod of magnetic material disposed in the breech and movable in a direction parallel with the axis of the barrel; a striker carried by the forward end of said rod; a permanent magnet mounted in said cavity of said guiding member vand acting on the rear end of said rod so as to attract it rearwardly; a guide socket of non-magnetic material connected to the rear end of Said rod and slidably surrounding said magnet thereby maintaining said rod yand said magnet in axial position relative to each other; a member which is longitudinally slidable in the breech and has a forward end operatively connected to said trigger and a rear end in the form of a fork, the two branches of the latter embracing said rod; a `ring slidable on said rod 'and resting against said fork; a striker coil spring wound over said rod and having `one end bearing against the forward end `of said rod and the other end bearing against said ring; a return coil spring surrounding said rod and having `one end ybearing against said obturating element and the other end bearing 4against said ring so as to bias the -latter toward the magnet.

References Cited in the file of this patent UNITED STATES PATENTS 710,124 Taskcr Sept. 30, 1902 1,067,004 Decker July 8, 1913 1,540,494 Olszowiec June 2, 1925 1,987,912 Rady et al Jan. 15, 1935 

